TOLEDO, Ohio ? The ad from Mitt Romney showed up on televisions here early Saturday morning without the usual public announcement that both campaigns typically use to herald their latest commercials: Chrysler, a bailout recipient, is going to begin producing Jeeps in China, an announcer says, leaving the misleading impression that the move would come at the expense of jobs here.

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And so began the latest, and perhaps most important, attempt by Mitt Romney to wrest Ohio into his column. His effort to do so is now intently focused, at times including statements that stretch or ignore the facts, on knocking down what is perhaps the most important component of President Obama’s appeal to blue-collar voters in Ohio and across the industrial Midwest: the success of the president’s 2009 auto bailout.

Mr. Obama’s relatively strong standing in most polls in Ohio so far has been attributed by members of both parties to the recovery of the auto industry, which has helped the economy here outperform the national economy. At the same time, the industry’s performance and the president’s claim to credit for it appear to have helped Mr. Obama among the white working-class voters Mr. Romney needs.

With the race under most expected circumstances coming down to Ohio, and Ohio potentially coming down to perceptions of how the candidates view the auto industry, Mr. Romney has spent the last few days aggressively trying to undercut Mr. Obama’s auto bailout narrative.

In the past few days his running mate, Representative Paul D. Ryan, has accused Mr. Obama of allowing the bailout to bypass nonunion workers at Delphi, a big auto parts maker with operations in Ohio; Mr. Romney has characterized Mr. Obama’s bailout plan as based on his approach; and Mr. Romney incorrectly told a rally in Defiance, Ohio, late last week outright that Jeep was considering moving its production to China. (Jeep is discussing increasing production in China for sales within China; it is not moving jobs out of Ohio or the United States, or building cars in China for export to the United States.)

It is a high-risk strategy: Jeep’s corporate parent, Chrysler, had already released a scathing statement calling suggestions that Jeep was moving American jobs to China “fantasies” and “extravagant”; news media outlets here and nationally have called the Romney campaign’s statements ? initially based on a poorly worded quotation from Chrysler in a news article that was misinterpreted by blogs ? misleading.

Mr. Obama’s campaign, seeking to maintain what it sees as its advantage in Ohio, responded on Monday by releasing a commercial calling Mr. Romney’s ad false and reiterating that Mr. Romney had opposed the bailout on the terms supported by Mr. Obama. And on Sunday it dispatched the investment banker who helped develop the bailout, Steven Rattner, here to discuss Jeep’s plans and the auto rescue with local news organizations.

Democrats are hoping that Mr. Romney’s latest move will draw a backlash in a city so dependent on Jeep, which has announced plans to add 1,100 jobs to an assembly plant here that is currently being refitted for the next iteration of what is now called the Jeep Liberty.

Bruce Baumhower, the president of the United Auto Workers local that oversees the major Jeep plant here, said Mr. Romney’s initial comments on moving production to China drew a rash of calls from members concerned about their jobs. When he informed them Chrysler was, in fact, is expanding its Jeep operation here, he said in an interview, “The response has been, ‘That’s pretty pitiful.’ ”

The fight over the auto bailout shows the enduring power of the issue but also its complexities in a campaign that is about both the strength of the economy and the size and role of government.

The auto bailout was one of the first major moves of Mr. Obama’s presidency, and gave Mr. Romney an early chance in opposing it to prove his conservative credentials.

Mr. Romney has portrayed himself as an automobile maven. As he frequently says in his stump speeches, his father was credited with keeping American Motors in business during the 1950s and early 1960s. (The company, it happens, owned Jeep from 1970 to 1987.)

Just as the incoming Obama administration was beginning to contemplate a bailout, Mr. Romney wrote an Op-Ed article in the The New York Times ? given the title by the newspaper “Let Detroit Go Bankrupt.’’ In the piece Mr. Romney wrote that in the event of a bailout, “You can kiss the American automotive industry goodbye.”

The plan the administration settled on first helped Fiat buy Chrysler and then put both Chrysler and General Motors into managed bankruptcies as part of a program that brought total government assistance for Detroit to almost $80 billion between the Obama and Bush administrations. Coming as the Tea Party was beginning to form, it seemed like risky politics for Democrats being accused of taking big government to an extreme.

At the third and last debate last week in Boca Raton, Fla., Mr. Romney emphasized his position that “these companies need to go through a managed bankruptcy, and in that process they can get government help and government guarantees.”

Mr. Romney has stepped up his offense on the issue since.

So it was that he told those at the exuberant rally on Thursday in Defiance, “I saw a story today that one of the great manufacturers in this state, Jeep, now owned by the Italians, is thinking of moving all production to China.”

Mr. Romney was apparently referring to a Bloomberg News article that said Jeep would return to manufacturing in China that had been misinterpreted by several conservative blogs to mean Jeep was shifting its production to China; the company made clear in a statement that Chrysler was only resuming production in China for Chinese consumers, which it had done for years before halting in 2009 before its sale to Fiat.

Mr. Romney’s ad treads carefully, with an announcer saying Mr. Obama “sold Jeep to the Italians, who are going to build Jeeps in China” and the screen flashing, “Plans to return Jeep output to China.”

Calling it “blatant attempt to create a false impression,” former Gov. Ted Strickland of Ohio, a Democrat, demanded Mr. Romney take it down on Monday. Stuart Stevens, a senior Romney adviser, disputed that the ad is misleading.

“Right now every Jeep built is built in America by an American and sold to the world,” he said. “Now instead of adding jobs in Toledo, they will be making Jeeps in China by the Chinese and selling them in China.”

Jeep began a joint manufacturing venture in China in 1984 and today makes some vehicles in Egypt and Venezuela. While it does produce cars for Chinese export here now, it has discussed returning some production to China since last year.